1. Field of the Invention
This invention relates to apparatus and methods for efficiently storing data, and more particularly to apparatus and methods for concurrently converting standard logical volumes to thin-provisioned logical volumes.
2. Background of the Invention
Customer growth over time varies and is often difficult to predict. As a result, it is often difficult to design and allocate storage resources that will adequately accommodate customer growth over a period of time while still ensuring that the storage resources are used in an efficient manner. Allocated but unused storage space increases up front costs, hardware, and power consumption. Thus, there is a powerful incentive to ensure that storage resources are allocated in an efficient manner. This involves a careful balancing act to ensure that enough storage space is available to accommodate growth while not allocating too much storage space that unnecessarily increases costs.
One current solution to the above-stated problem is to implement thin provisioning. Thin provisioning allows storage space to be allocated on a just-enough and just-in-time basis as data is written. This differs from conventional storage allocation techniques (also called “fat provisioning”) which allocates storage space up front and often results in large amounts of unused storage space. Thin provisioning, by comparison, eliminates most of the free space in storage volumes and helps to avoid poor storage utilization rates, often as low as ten percent, that occur using traditional “fat provisioning” allocation techniques. When properly implemented, thin provisioning can significantly reduce the amount of time system administrators spend allocating and managing storage.
Although thin provisioning may be used to more efficiently utilize storage capacity, there is currently no method to concurrently convert traditional storage volumes (storage volumes using “fat provisioning” techniques) to more efficient thin-provisioned volumes. Current techniques for performing fat to thin conversions may involve performing block-by-block copies from a standard fat volume to a new thin-provisioned volume. Other approaches include backing up the standard fat volume at a file level, and then restoring the files to a new thin volume. Although effective, these approaches can be time-consuming and disrupt I/O to the volumes.
In view of the foregoing, what are needed are apparatus and methods to concurrently convert standard logical volumes to more efficient thin-provisioned volumes. Such an apparatus and method would ideally perform the conversion rapidly without significantly disrupting I/O to the volume.